The larynx is a structure of the
respiratory tract that is inferior to the pharynx and superior to the trachea.
It encloses the vocal cords that enable one to speak and sing, which is why it
is often referred to as the “voice box.” In addition, the larynx is responsible
for preventing food and drink from obstructing the airway, allowing an
individual to consume and breath without choking. Its structure is formed by
strong and flexible cartilages and muscles that are connected by elastic
tissue. The cartilages of the larynx include the thyroid, cricoid, and
epiglottic, arytenoid, and corniculate cartilages.
thyroid cartilage, represented by a large piece of foam colored to be blue with
marker in my model, is the largest cartilage in the larynx. It is composed of
two laminae that are anteriorly connected at the laryngeal prominence, a
protrusion of the front of the neck often referred to as the “Adam’s apple.” The
Adam’s apple is usually larger in males than in females, since male sex
hormones affect the development of the laryngeal prominence, causing the angle
between the left and right laminae to be more acute in males. A v-shaped indentation
called the thyroid notch is superior to the laryngeal prominence, creating a divot
in the center of the thyroid cartilage. The laminae extend to create superior
and inferior horns, in which the superior horn connects the thyroid cartilage to
the hyoid bone and the inferior horn attaches to the cricoid cartilage.
The cricoid cartilage, represented by
green modeling clay in my model, forms the base of the larynx and is found
between the thyroid cartilage and the trachea. It is composed of hyaline
cartilage and takes on a ring-like shape, with the back of the structure being
broader than the front.
The epiglottis, represented by a red piece
of paper in my model, is a flap-like structure that presses downward to cover
the glottis and prevents one from choking on food and liquids that would
otherwise enter the air passages. Foods and liquids can then pass into the
gastrointestinal tract, where they will be digested. In its relaxed state, the
epiglottis stands erect to allow air to enter through the larynx and into the
lungs, enabling an individual to breath. This leaf-shaped sheet of cartilage covers
the superior opening into the larynx and is connected by the thyroepiglottic
ligament, which attaches to the hyoid bone.
The hyoid bone, represented by a white
piece of foam in the model, is a u-shaped bone that is inferior to the mandible.
While the hyoid bone is often associated with the skull, it is not connected to
it. In fact, it is the only bone in the entire body that is not attached
directly to another bone. The hyoid bone acts as an anchor for muscles, specifically
those of the tongue.
Two pyramidal arytenoids, represented by
pink modeling clay in my model, sit on top of the cricoid cartilage and are the
structures in which the vocal ligaments and vocal folds attach. Two cone-like corniculate
cartilages fasten to the superior surfaces of the arytenoids, which are represented
by smaller projections of pink modeling clay.
The larynx houses two pairs of horizontal
vocal folds, formed by connective and muscle tissue with a mucous membrane
covering, that extend from the lateral walls toward the midline of the larynx.
The false vocal folds are the superior folds and do not generate sound. They
instead contribute to closing the air passages during swallowing. The true
vocal cords, however are responsible for producing sound. When air is pushed
through these lower folds of muscle tissue, the true vocal folds vibrate in a horizontal
motion, resulting in the generation of sound waves. These sound waves can then
be transformed into words through different combinations in tongue placement,
lip movement, and space within the oral cavity. The pitch of sound is
manipulated by muscles that put tension on the vocal cords. The pitch is raised
by an increase in tension and is lowered by a decrease in tension. One can also
increase the volume of their voice by forcing more air across their vocal